SEATTLE, Oct. 19 /PRNewswire-FirstCall/ -- Trubion
Pharmaceuticals, Inc. (NASDAQ:TRBN) today announced favorable safety
and efficacy data following administration of a second course (R2)
of re-treatment with 800 mg of TRU-015 for rheumatoid arthritis
(RA). These data are the latest results from the ongoing open-label
re-treatment portion of the Phase 2b (15002) RA study of TRU-015.
Pfizer Inc. and Trubion are collaborating on the development of
TRU-015 for the treatment of autoimmune and inflammatory diseases,
including RA.

Data from the open-label re-treatment phase of the Phase 2b
study demonstrate that repeat administration with TRU-015 is
generally well-tolerated and results in sustained improvement in
the signs and symptoms of RA. Results were presented at the 2009
American College of Rheumatology (ACR)/Association of Rheumatology
Health Professionals (AHRP) Annual Scientific Meeting in
Philadelphia. A copy of the poster is available in the investor
section of Trubion's website (http://investors.trubion.com/index.cfm).

The Phase 2b trial is a double-blind, placebo-controlled,
randomized study that is designed to evaluate the safety,
tolerability, pharmacodynamics (PD), pharmacokinetics (PK) and
clinical activity of repeat doses of TRU-015. Of the 276 original
patients who began the study, 240 (204 of whom were
rheumatoid-factor positive, or RF+) entered the first open-label
re-treatment portion (R1) of the trial. Trubion announced the first
course of re-treatment data from this study at the 2009 EULAR
Annual Meeting in June 2009.

A total of 226 patients from R1 were enrolled in the second
re-treatment portion (R2) of the trial. At 24 weeks after the
second re-treatment course, subjects in the group that had received
800 mg of TRU-015 in the initial treatment and re-treatments R1 and
R2 achieved ACR 20, 50 and 70 response rates of 72%, 39% and 21%,
respectively. Results were similar to the response rates achieved
in R1 (70%, 40% and 23%, respectively).

Numeric reductions in the Disease Activity Score 28 (DAS28), the
Health Assessment Questionnaire (HAQ), and C-reactive protein (CRP)
seen at the end of the double-blind treatment and first
re-treatment periods were maintained or continued to improve during
the open-label re-treatment period.

Infusions were generally well-tolerated and no patient
experienced a serious adverse event on the day of infusion. Eight
patients (3.5%) enrolled in the trial experienced serious adverse
events during the second re-treatment period. This is similar to
observations made during the initial double-blind phase of the
study (placebo 2%, 800 mg group 2%) and R1 (4%).

"We have now administered more than 1,300 doses of TRU-015 over
four and a half years and continue to see positive and sustained
results in RA patients. This reinforces our belief that TRU-015
could represent a differentiated treatment option when compared to
other offerings on the market or in development," said Peter
Thompson, M.D., FACP, president, CEO and chairman of Trubion. "We
believe a key to this differentiation should include data
demonstrating both initial improvement in signs and symptoms and
sustained improvement following multiple courses of
re-treatment."

About Trubion

Trubion is a biopharmaceutical company that is creating a
pipeline of novel protein therapeutic product candidates to treat
autoimmune and inflammatory diseases and cancer. The Company's
mission is to develop a variety of first-in-class and best-in-class
product candidates, customized for optimal safety, efficacy and
convenience that it believes may offer improved patient
experiences. Trubion's current product candidates are novel
single-chain protein, or SMIP, therapeutics, and are designed using
its custom drug assembly technology. Trubion's product pipeline
includes CD20-directed SMIP therapeutics such as TRU-015 and
SBI-087 for autoimmune and inflammatory diseases, developed under
the Company's Pfizer collaboration. Trubion's product pipeline also
includes TRU-016, a novel CD37-targeted therapy for the treatment
of B-cell malignancies developed under the company's Facet Biotech
collaboration. In addition to Trubion's current clinical stage
product pipeline, the Company is also developing its multi-specific
SCORPION technology, both for targeting cell-surface molecules like
CD79b and HLA-DR, as well simultaneously neutralizing soluble
ligands like TNF and IL-6. More information is available in the
investors section of Trubion's website: http://investors.trubion.com/index.cfm.

Forward-Looking Statements

Certain statements in this release may constitute
"forward-looking statements" within the meaning of Section 21E of
the Securities Exchange Act of 1934 and Section 27A of the
Securities Act of 1933. These statements include, but are not
limited to, those related to the potential development and
commercialization of TRU-015. These statements are based on current
expectations and assumptions regarding future events and business
performance and involve certain risks and uncertainties that could
cause actual results to differ materially. These risks include, but
are not limited to, risks associated with the Company's Pfizer
collaboration, including the risk that the Company and Pfizer are
unable to advance TRU-015 clinical development programs and
regulatory applications and action at the expected rate, the risks
that the Company is unable to develop or commercialize TRU-015, and
such other risks as identified in the Company's quarterly report on
Form 10-Q for the period ended June 30, 2009, and from time to time
in other reports filed by Trubion with the U.S. Securities and
Exchange Commission. These reports are available on the Investors
page of the company's corporate website at http://www.trubion.com/. Trubion undertakes no
duty to update any forward-looking statement to conform the
statement to actual results or changes in the Company's
expectations.

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